Regular expressions can vary from simple to WTF. Usually they tend
toward the latter. What most don't realized, or are too lazy to use, is
that regular expressions can be made to include friendly whitespace and
comments. CFEngine is no exception.

CFEngine's autonomous automation means that your policy, mistakes and
all, will be duplicated quickly to all of your hosts. --- Potentially
tens of thousands of them. When I taught martial arts it was humbling
to watch a class of thirty duplicate my incorrect movement. I didn't
know, because I didn't test myself. In martial arts I was simply
embarrassed, but in configuration management, mistakes could cost me a
raise or even my job. Testing is the paramount best practice for
CFEngine. Let me tell you what I have learned.